1. Technical Field
The present invention relates to a vehicle safety apparatus and, in particular, to an inflator for an inflatable vehicle occupant protection device, such as a side curtain, which remains inflated for an extended period of time.
2. Description of the Prior Art
It is known to inflate a vehicle occupant protection device, such as an air bag, to help protect a vehicle occupant. The protection device is inflated by inflation fluid from an inflator. One type of protection device is a side curtain. The side curtain is inflatable into a position between the vehicle occupant and the vehicle side structure to help protect the vehicle occupant in the event of a side impact to the vehicle.
It is known to tailor the output pressure of an inflator, in order to inflate an air bag or side curtain in a predetermined manner over a period of time. For example, it is known to inflate a side curtain initially with inflation fluid at a relatively high pressure and flow rate, then to maintain the side curtain inflated for an extended period of time with a continued flow of inflation fluid at a relatively low rate. Known inflators which can effect such an extended inflation of a side curtain use one or more ignitable pyrotechnic charges which can burn for an extended period of time.